Chapter 5 Systems Analysis and Design in a

Chapter 5 Systems Analysis and Design in a Changing World, 6 th Edition 1

Extending the Requirements Models Chapter 5 Systems Analysis and Design in a Changing World 6 th Ed Satzinger, Jackson & Burd

Chapter 5 Outline l l l Use Case Descriptions Activity Diagrams for Use Cases The System Sequence Diagram— Identifying Inputs and Outputs The State Machine Diagram—Identifying Object Behavior Integrating Requirements Models Systems Analysis and Design in a Changing World, 6 th Edition 3

Overview l l l Chapter 3: Modelling use cases (Processes) Chapter 4: Modelling classes (data) Chapter 5: Modelling use cases, in more detail l l l l including actors Stakeholders scenarios Preconditions post conditions the flow of activities Exceptions etc Systems Analysis and Design in a Changing World, 6 th Edition 4

Use Case Descriptions l Brief use case description l Good initially, or for simple cases Systems Analysis and Design in a Changing World, 6 th Edition 5

Fully Developed Use Case Description Use case: Create customer account Systems Analysis and Design in a Changing World, 6 th Edition 6

Fully Developed Use Case Description Create customer account (part 1 ) Systems Analysis and Design in a Changing World, 6 th Edition 7

Fully Developed Use Case Description Create customer account (part 2 ) Systems Analysis and Design in a Changing World, 6 th Edition 8

Another Fully Developed Use Case Description Example Use case Ship items Systems Analysis and Design in a Changing World, 6 th Edition 9

Fully Developed Use Case Description Ship items (part 1 ) Systems Analysis and Design in a Changing World, 6 th Edition 10

Fully Developed Use Case Description Ship items (part 2 ) Systems Analysis and Design in a Changing World, 6 th Edition 11

UML Activity Diagram for Use Case Create Customer Account Note: this shows flow of activities only Systems Analysis and Design in a Changing World, 6 th Edition 12

UML Activity Diagram for Use Case Fill shopping cart Note: this shows use case with <> reltionship Systems Analysis and Design in a Changing World, 6 th Edition 13

System Sequence Diagram (SSD) Notation Systems Analysis and Design in a Changing World, 6 th Edition 14

SSD Message Examples with Loop Frame Systems Analysis and Design in a Changing World, 6 th Edition 15

SSD Message Examples Opt Frame (optional) Alt Frame (if-else) Systems Analysis and Design in a Changing World, 6 th Edition 16

Message Notation Systems Analysis and Design in a Changing World, 6 th Edition 17

SSD for Create customer account Use case Systems Analysis and Design in a Changing World, 6 th Edition 18

SSD for Ship items Use Case Systems Analysis and Design in a Changing World, 6 th Edition 19

State Machine Diagram l State machine diagram l l State l l A condition during an object’s life when it satisfies some criterion, performs some action, or waits for an event Transition l l A UML diagram showing the life of an object in states and transitions The movement of an object from one state to another state Action Expression l A description of activities performed as part of a transition Systems Analysis and Design in a Changing World, 6 th Edition 20

State Machine Diagram (continued) l Pseudo state l l Origin state l l The original state of an object before transition Destination state l l The starting point of a state machine diagram (black dot) The state to which the object moves after the transition Guard condition l A true false test to see whether a transition can fire Systems Analysis and Design in a Changing World, 6 th Edition 21

State Machine Diagram for a Printer Systems Analysis and Design in a Changing World, 6 th Edition 22

Composite States l l State containing other states and transitions Printer can be On and either Idle or Working Systems Analysis and Design in a Changing World, 6 th Edition 23

Concurrent Paths l l Multiple paths in composite state Printer On paths are independent Systems Analysis and Design in a Changing World, 6 th Edition 24

Steps for Developing State Machine Diagram 1. 2. 3. 4. 5. Review the class diagram and select classes that might require state machine diagrams For each class, make a list of status conditions (states) you can identify Begin building diagram fragments by identifying transitions that cause an object to leave the identified state Sequence these states in the correct order and aggregate combinations into larger fragments Review paths and look for independent, concurrent paths Systems Analysis and Design in a Changing World, 6 th Edition 25

Steps for Developing State Machine Diagram (continued) Look for additional transitions and test both directions Expand each transition with appropriate message event, guard condition, and action expression Review and test the state machine diagram for the class 6. 7. 8. l l Make sure state are really state for the object in the class Follow the life cycle of an object coming into existence and being deleted Be sure the diagram covers all exception condition Look again for concurrent paths and composite states Systems Analysis and Design in a Changing World, 6 th Edition 26

RMO Domain Class States for Sale. Item Object Systems Analysis and Design in a Changing World, 6 th Edition 27

Final State Machine Diagram for Sale. Item Object l l add. Item() and archive() transitions added mark. Back. Ordered() transition added Systems Analysis and Design in a Changing World, 6 th Edition 28

Initial State Machine Diagram for RMO Sale Object Systems Analysis and Design in a Changing World, 6 th Edition 29

Final State Machine Diagram for Sale Object Systems Analysis and Design in a Changing World, 6 th Edition 30

Integrating Requirements Models Systems Analysis and Design in a Changing World, 6 th Edition 31

Problems and Exercises l 1(i and ii), 2, 3 Systems Analysis and Design in a Changing World, 6 th Edition 32